In the manufacture of large-capacity memory devices, the occurrence of a defective bit due to the memory principle and the variation in processes cannot be avoided. In this regard, a nonvolatile memory device is proposed that includes a main memory and a supplementary memory that stores the position information of a defective bit in the main memory etc., prohibits using the defective bit identified, and uses an alternative bit.
Here, in those cases where a nonvolatile memory device is mounted, the nonvolatile memory device may be temporarily exposed to a high temperature.
For example, the semiconductor chip of a nonvolatile memory device, LSI, etc. is electrically connected to the external circuit through an operation called solder reflow during mounting. In the solder reflow process, since lead-free solder is used as a bonding material, the whole circuit including the semiconductor chip is generally heated to about 250° C. to 260° C. by infrared (IR) heating. There is also a reflow method in which only the electrode of the connection portion is exceptionally heated by ultrasonic heating or laser heating to suppress the increase in the temperature of the semiconductor chip portion. However, since infrared heating is much more excellent in mass productivity and the reliability of the joint portion, the reflow method using infrared heating is most widely used.
In the case where the nonvolatile memory device is thus temporarily exposed to a high temperature, if the information stored in the supplementary memory is undesirably erased, it becomes necessary to perform another electrical characteristic test to identify the defective bit and store the position information of the defective bit etc. into the supplementary memory again.
In view of this, a nonvolatile memory device is proposed that includes a supplementary memory having a data erase temperature higher than the data erase temperature of the main memory.
However, since the configuration of the main memory and the configuration of the supplementary memory are different, the productivity may be reduced.